Backport MR #2163 (edited to cover vbox) to fix VM cursor offset (#2063969)

2163-edited.patch

@@ -0,0 +1,63 @@
+From e686da9ddedd820d3a7c3c21033c48276c251636 Mon Sep 17 00:00:00 2001
+From: Xaver Hugl <xaver.hugl@gmail.com>
+Date: Sun, 20 Mar 2022 05:12:48 +0100
+Subject: [PATCH] backends/drm: fall back to legacy mode in virtual machines
+
+Virtual machines aren't properly supporting atomic mode setting yet, which
+causes the cursor to be offset, and will cause more issues with overlay
+planes. In order to prevent that from impacting users, fall back to legacy,
+unless KWIN_DRM_NO_AMS is set.
+
+BUG: 427060
+FIXED-IN: 5.24.4
+---
+ src/backends/drm/drm_gpu.cpp | 11 +++++++----
+ src/backends/drm/drm_gpu.h   |  1 +
+ 2 files changed, 8 insertions(+), 4 deletions(-)
+
+diff --git a/src/backends/drm/drm_gpu.cpp b/src/backends/drm/drm_gpu.cpp
+index 51b8719f57..26d6b27b04 100644
+--- a/src/backends/drm/drm_gpu.cpp
++++ b/src/backends/drm/drm_gpu.cpp
+@@ -75,9 +75,10 @@ DrmGpu::DrmGpu(DrmBackend *backend, const QString &devNode, int fd, dev_t device
+     m_addFB2ModifiersSupported = drmGetCap(fd, DRM_CAP_ADDFB2_MODIFIERS, &capability) == 0 && capability == 1;
+     qCDebug(KWIN_DRM) << "drmModeAddFB2WithModifiers is" << (m_addFB2ModifiersSupported ? "supported" : "not supported") << "on GPU" << m_devNode;
+ 
+-    // find out if this GPU is using the NVidia proprietary driver
++    // find out what driver this kms device is using
+     DrmScopedPointer<drmVersion> version(drmGetVersion(fd));
+     m_isNVidia = strstr(version->name, "nvidia-drm");
++    m_isVirtualMachine = strstr(version->name, "virtio") || strstr(version->name, "qxl") || strstr(version->name, "vmwgfx") || strstr(version->name, "vboxvideo");
+     m_gbmDevice = gbm_create_device(m_fd);
+ 
+     m_socketNotifier = new QSocketNotifier(fd, QSocketNotifier::Read, this);
+@@ -148,9 +149,11 @@ clockid_t DrmGpu::presentationClock() const
+ void DrmGpu::initDrmResources()
+ {
+     // try atomic mode setting
+-    bool tmp = false;
+-    bool noAMS = qEnvironmentVariableIntValue("KWIN_DRM_NO_AMS", &tmp) != 0 && tmp;
+-    if (noAMS) {
++    bool isEnvVarSet = false;
++    bool noAMS = qEnvironmentVariableIntValue("KWIN_DRM_NO_AMS", &isEnvVarSet) != 0 && isEnvVarSet;
++    if (m_isVirtualMachine && !isEnvVarSet) {
++        qCWarning(KWIN_DRM, "Atomic Mode Setting disabled on GPU %s because of cursor offset issues in virtual machines", qPrintable(m_devNode));
++    } else if (noAMS) {
+         qCWarning(KWIN_DRM) << "Atomic Mode Setting requested off via environment variable. Using legacy mode on GPU" << m_devNode;
+     } else if(drmSetClientCap(m_fd, DRM_CLIENT_CAP_ATOMIC, 1) != 0) {
+         qCWarning(KWIN_DRM) << "drmSetClientCap for Atomic Mode Setting failed. Using legacy mode on GPU" << m_devNode;
+diff --git a/src/backends/drm/drm_gpu.h b/src/backends/drm/drm_gpu.h
+index 97c2d8ddc2..1e1f7e3b15 100644
+--- a/src/backends/drm/drm_gpu.h
++++ b/src/backends/drm/drm_gpu.h
+@@ -118,6 +118,7 @@ private:
+     bool m_atomicModeSetting;
+     bool m_addFB2ModifiersSupported = false;
+     bool m_isNVidia;
++    bool m_isVirtualMachine;
+     clockid_t m_presentationClock;
+     gbm_device* m_gbmDevice;
+     EGLDisplay m_eglDisplay = EGL_NO_DISPLAY;
+-- 
+GitLab
+

kwin.spec

@@ -17,7 +17,7 @@
 
 Name:    kwin
 Version: 5.24.3
-Release: 2%{?dist}
+Release: 3%{?dist}
 Summary: KDE Window manager
 
 # all sources are effectively GPLv2+, except for:
@@ -40,6 +40,12 @@ Source0: http://download.kde.org/%{stable}/plasma/%{version}/%{name}-%{version}.
 
 ## proposed patches
 
+# Fallback to legacy mode in VMs to fix cursor offset bug:
+# https://invent.kde.org/plasma/kwin/-/merge_requests/2163
+# https://bugzilla.redhat.com/show_bug.cgi?id=2063969
+# edited to add 'vboxvideo' for VirtualBox
+Patch0: 2163-edited.patch
+
 # Base
 BuildRequires:  extra-cmake-modules
 BuildRequires:  kf5-rpm-macros
@@ -368,6 +374,9 @@ make test ARGS="--output-on-failure --timeout 10" -C %{_target_platform} ||:
 
 
 %changelog
+* Mon Mar 21 2022 Adam Williamson <awilliam@redhat.com> - 5.24.3-3
+- Backport MR #2163 (edited to cover vbox) to fix VM cursor offset (#2063969)
+
 * Thu Mar 10 2022 Marc Deop <marcdeop@fedoraproejct.org> - 5.24.3-2
 - Rebuild (qt5)